In this paper we present LP based MPC solutions to two classes of large scale problems : (i) plant-wide control, and (ii) CD control in a paper machine. The former problem represents a challenge of considerable dynamic complexity given the interactions inherent in a multiple-unit plant. An application is presented for a DuPont benchmark problem. While the latter problem has relatively benign dynamics, the input-output dimensionality is significant (approximately 400x400), and the required solution times are on the order of seconds. A customized algorithm is presented for the latter problem to enable real-time implementation.